Noninflammable fabric and process of making the same



Patented Aug. 25, 1931 UNITED STATES PATENT OFFICE 'ALAN F. RANDOLPH, OF VERONA, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, 'J-O THE CELASTIC CORPORATION, OF WILMINGTON, DELAWARE, A CORPORATION 01' DELAWARE NONINFLAMMAIBLE FABRIC AND PROCESS OF MAKING THE SAME ll'o Drawing.

This invention relates to non-inflammable fabrics, both the article and the process of makin the same. Particularly it relates to treate fabrics of the type that contains in I the intersticesof the fabric body or the pile, or both, a material which, on being treated with a suitable solvent, will cause the treated fabric to become flaccid, and which, on removal of the solvent, will-cause the fabric (which in the meantime has been given a desired shape) to retain a desired shape.

In, accordance with the present invention any suitable fabric, either woven or structureless, as cloth or felt, is first thoroughly impregnated with a dope containing the desired stiffening material, and fire-retardants; then, without drying, the goods are passed through a bath of a character to precipitate in the goods the stiffening material, carrying with it the fire-retardant or retardants, a er which the goods are dried. In use, the goods. are quickly treated with a solvent for the stiffening material, sufficiently to render the goods flaccid but not sufficiently to remove the material. The goods are then shaped, and the solvent then dried out. -It will be understood that the precipis Th tating bath, and the colloiding bath are prefin agent or a ents. v

n preferab e accordance w1th the invention, the primary material of the impregnatin dope is a cellulose ester, as pyroxylin or ce lulose acetate; the fire-retardant isa substance which, on heating, will evolve a fire-smothering gas, for example gypsum, CaSO,.2H O; the volatile solvent in the dope may be denatured alcohol and acetone, and a fixable solvent. or plasticizer may be camphor or an aromatic phosphate, such as tricresyl phosphate, such a phosphate being particularly desirable since it itself is a fireretardant. The precipitating bath may bewater. And the. solvent for rendering the material flaccid may be denatured alcohol andacetbne, or, in order to ensure that the goods will not stiflen too rapidly, due to prompt eva oration of the solvent, a'mixture of alco 01 and a high'boilin'g' solvent, such as diacetone alcohol mayi'be used.

erably such as not to remove the fire-retard-- ammonium h h t t t Application filed September 9, 1926. Serial No. 134,579.

;Wi thout restricting the invention thereto, a su1table formula for, the impregnating mixture may be (parts by weight) Range Preferred Pyroxylin 100 100 100 Camphor 0- 35 3O Tricresyl phosphate 0-, 33 Gypsum 100- 250 200 Volatile solvent 500-1000 650 pends on the degree of impairment of stiifness of the fabric permissible in any particular case; and slmilarly the amount of gypsum or the like is limited by the degree of brittleness and .friability permissible. e gypsum is illustrative of a variety of other substances, such as calcium tartrate, The pyroxylm may, of course, be replaced, in whole or 1n part, by other cellulosic derivatives as cellulose acetate.

While. more particular mention has been made above of cellulosic dopes, it will be understood that other materials may be used for impregnating the goods; for example, there may be used various gums and resins, or rosin. As is evident, when such materials are used they should be dissolved in suitable solvents for making a proper dope. The precipitating bath should be suitable for the particular case in hand and the fire-retarding constituent should beone that is properly consistent with the dope and the precipitating bath. Also, the solvent used for making the goods flaccid should be properly consistent with the primary material'used for impregnating the goods and also with the fire-retarding substance. To illustrate, whena using gum 'copal, the impregnating dope, the

The amount finished shaped goods.

- pregnating dope.

precipitating liquid and the solvent for making the goods flaccid may be as follows Partsby weight Gum copal Gypsum 100 Acetone 25-50 In this case the precipitating liquid may be water, and the solvent used for making the goods flaccid may be acetone with or without partial replacement by a high boiling solvent.

The practical making of goods in accordance with the invention will be understood by those skilled in the art, the presence of the fire-retarding agent introducing no complications intothe general procedure of applying the dope, precipitating the stifi'ening material, e. g. pyroxylin, making the goods flaccid, shaping them, and permitting the solvents to dry out. However, in brief, the goods to be treated, say woven fabric. are passed through the impregnating bath (e. g. pyroxylin) until thoroughly impregnated, the goods being preferably distorted or kneaded during passage by any suitable mechanical means, or by hand, to facilitate the penetration of the dope. The goods are then passed into the precipitating bath (e. g. Water) and immersed therein, desirably with kneading, until precipitation is completed, which will be indicated by the fact that squeezing of the goods does not bring to the surface particles or drops of the colloid solution or dope, easily identified by its gelatinous character. The fabric is now withdrawn from the water bath and dried; and the impregnating material proper, e. g. pyroxylin, and the fire-retarding agent will e found in or on thefabric and entangled and interlocked with the fibres thereof. In due course the goods are uickly dipped in the solvent bath, merely su ciently to render them flaccid and without substantial removal of the deposited substances, are shaped and then the solvents evaporated, giving the The goods may be formed into blanks of the final shape at such time as desired, as prior to the beginning of the process.

As to the character of the fire-retardant,- it is not important whether or not the fireret-ardant is soluble or insoluble in the solvents used in makin up the impregnating dope. Even though it be insoluble difficulty with settling out 1s not likely to be experienced in the time which would ordinarily elapse between the making up and the use of the impregnating dope. The fire-retardant is, of course, used in a very finely divided condition, and is easily supported by the imfire-retardant insoluble in -the precipitating bath and in the flaccidity-iniparting bath. If, however, 'it

It is desirable to use a be desired to use a soluble retardant the technique of the precipitating-bath treat-'- ment may be modified to minimize the kneading action and to allow the surface to become sealed by the precipitate promptly. The precipitating liquid would then penetrate to the centre of the fabric relativel slowly. Under such conditions there woul be relatively little loss of the fire-retardant substance even though it' were definitely soluble in the precipitating path. As to the flaccidity-imparting bath, even though the fireretardant be soluble in it, the immersion in this bath is very brief and substantial amounts of the fire-retardant would remain in the fabric. Thus, such a substance as urea would be soluble in acetone-alcohol, also in water, and also in the recolloiding or flaccidity-imparting bath, yet, with the precipitating treatment properly carried out a large percentage of the urea originally introduced would survive in the finished goods, as a result of entrainment with the precipitate and occlusion by it.

The fire-retardant particularly mentioned 00 above, gypsum, is, of course, substantially insoluble in the liquids ordinarily used, i. e. acetone and. alcohol in the impregnating bath, water in the precipitating liquid, and

alcohol and diacetone alcohol in the recol- 96 loiding solvent.

Returning to the treatment of the fabric in the precipitating bath, an immersion of the goods for about one-half hour therein should generally be ample. If desired, the i goods may be passed over idler rolls in the tank, or rolled up and unrolled occasionally, to facilitate the precipitation.

I claim:

1. As an article of manufacture, a porous fabric having in and through the interstices thereof, and carried within the same as a filling therefor, a powdered colloidal material in precipitated form, forming a orous deposit capable of ready penetration y solvents therefor, together with a fire-retardant, such retardant being deposited within, entangled in and distributed through the deposit of colloidal material.

2. As an article of manufacture, a porous fabric having in and through the interstices thereof, and carried within the same as a filling therefor, a powdered cellulose ester in precipitated form, forming a porous deposit capable of ready penetration by solvents therefor, together with a fire-retardant'capable of evolving a fire-smothering gas u n heating, such retardant being deposited within, entangled in and distributed through the cellulose ester deposit.

3. As an article of manufacture, a porous fabric having in and through the interstices thereof, and carried within the same as a able of ready penetration by solvents therei or together with gypsum as a fire-retardant, sue gydpsum being deposited within and distribute through the pyroxylin deposit.

4. The method of roducing a pable of being made accid, shaped and stifiened by virtue of a deposited and carried colloidal material, and embodying a fire-retarding ent deposited within, entangled in, and

distn uted through the colloidal material,

which method comprises: preparing a bath of a colloidal material, insoluble in the hereafter named precipitating bath, and containing a normally solid fire-retarding agent, immersing a porous fabric in said bath, and thereafter immersing the fabric in a precipitating bath thus to simultaneously deposit the colloidal material in powdered precipitated formin and through the interstices of the fabric together with the fire-retarding agent entangled with and distributed through the colloidal material.

5. Themethod of pable of being made accid, shaped and stifiened by virtue of a deposited and carried colloidal materiali and embodying a gas-evolving, fire-retar ing agent {deposited within, entangled in, and distributed through the colloidal material, which method comprises:

. preparing a bath of a colloidal material, in-

soluble in the hereafter named precipitating bath, and containing a normally solid fireretarding agent capable of evolving a firesmotherin gas upon heating, immersin a porous fa ric in said bath, and therea r immersing the fabric in a precipitating bath thus to simultaneously deposit the colloidal material in powderedprecipitated form in and through the interstices of the fabric togetherwith the gas-evolving, fire-retarding agent entangled with and distributed through the colloidal material.

In testimony ALAN, F. RANDOLPH.

abric careducing a fabric cawhereof I aflix my signature. 4 

